Curve pen adapter



May 26, 1953 G- L,ORY 2,639,506

CURVE PEN ADAPTER Filed Dec. 24. 1947 IN VEN TOR. GEORGE LOH Y A TTORNEZ Patented May 26, 1953 UNITED STATES PATENT OFFICE CURVE PEN ADAPTER George Lory, L Angeles, Calif.

Application December 24, 1947, Serial No. 793,583

6 Claims. 1

This invention relates to drafting instruments and in particular to ruling pens suitable for making straight or curved lines with India ink and the like.

The object of this invention is to provide a device that will convert a straight-bladed ruling pen into a so-called curve pen without the necessity of curving the blades so that the point of the pen i offset from the longitudinal axis passing through the axis of the instrument.

A related object of this invention is to provid a pen that can be used satisfactorily either as a conventional straight-bladed ruling pen suitable for making straight lines or as a curve pen for inking curved lines such as are required on contour maps.

A further object of this invention i to provide a device that will reduce the cost of manufacturing ruling pens of the above type and will permit increased production.

A curve pen in its usual form is a ruling pen having a pair of curved blades instead of the conventional straight blades. The blades are curved to place the point of the pen eccentric with the line passing through the longitudinal axis of the instrument handle. The blades are generally made integral with a blade support which is securely attached to a cylindrical shaft of small diameter extending the length of the handle of the instrument. The outer portion of the pen handle is preferably made in the form of a sleeve bored to permit the shaft to rotate freely therein. When the concentric shaft is free to turn the offset pen points will follow any curve since any slight pressure due to a change in direction will cause the tip of the pen blades to realine themselve with the inner surface of the blades automatically positioning themselves parallel to the edge of any curve being traced. A locking cap nut is provided at the upper end of the handle which threads on the shaft and converts the rotating sleeve and shaft into a rigid handle when the nut is tightened against the upper end of the sleeve.

. In using a curve pen the best results are ob tained by holding the pen in a nearly vertical position with the locking nut loosened so that the handle can rotate freely. The eccentric positioned pen points responds quickly when held in this position to any change in direction whether slight or abrupt and will produce lines of uniform thickness at all points along the curve.

The practice heretofore in manufacturing curve pens has been to take straight ruling pen blanks, milling or cutting the pen blanks to give them the desired curve which i generally in the form of an elongated S, finish the curved pieces into blades, harden the blades and then finish the points by grinding. This method of making curve pens requires considerable time and material, making the cost of such pens high. In addition exceptional skill and care are required on the part of the maker to insure that both of the finished blades have the same curve and length.

All the difficulties encountered in making a single curve pen are greatly increased when it is "tached to a handle.

the operator to adjust the thickness of the line made by each pen. A railroad pen, therefore, comprises two pens each having a flexible blade with both of the pens connected to the main sup-' porting bridge member by a flexible member to permit adjustment of the distance between the points as desired.

In manufacturing a railroad curve pen, usually referred to as a double curve pen, considerable difiiculty is encountered in making two pens having exactly the same curve and length. This is necessary to insure that both pens will align themselves parallel to the edge of the guide curve or line at all times, if one of the pens is longer or has a difi'erent degree of curvature than the other, the two pens will not operate in the desired manner.

The manufacture of a double curve pen is obviously accompanied by greater difiiculties than are encountered in making a single curve pen such as described above.

According to my invention, I provide a device which permits a straight-bladed pen to serve satisfactorily either as a ruling pen or as a curve pen regardless of whether it is a single straightbladed ruling pen or a straight-bladed railroad requires only one instrument to serve either a a ruling pen or curve pen.

j I accomplish this by providing an adapter haning slightly towards the front to provide clearance and enable the hinge to describe the desired arc. Viewed from the side as shown in Fig. 2 fork 48 is generally rectangular in shape and the bottom edge of the groove and the sides of the fork serve as a stop for the lower hinge member when it has travelled the required are. The hinge can also be constructed to permit the lower member to describe a limited arc on either side of center as shown in Fig. 2a. This arrangement of the fork and tongue is shown by way of example and may be reversed if desired. When the hinge is straight the axis of the two hinge members will fall on the line described by the axis of shaft 45. The bottom surface of lower hinge member 49 is provided with a centrally located hole 5| threaded to receive threaded projection ll extending from the bridge of the pen.

A sleeve 52 is provided with an axial bore 53 of sufficient diameter to permit shaft 45 to turn freely therein. The sleeve extends from the end of hinge member 48 to a point beyond the lower end of the threads on the upper end on central shaft 45. The central span of sleeve 52 is preferably counterbored forming an annular clearance 54 between shaft 45 and the inner surface of the counterbore in sleeve 52. This eliminates excess weight and friction leaving only the lower portion of sleeve 52 in direct contact with the shaft.

The upper end of sleeve 52 is held in concentric position by a locking cap nut 55. The outer surface of lock cap nut 55 is preferably cylindrical in shape and is of approximately the same diameter as the outer diameter of sleeve 52. The upper portion'of cap nut 55 is made of sufiicient length 55 to provide a suitable thumb grasp which is preferably knurled to facilitate tightening and loosening. The diameter of the nut below the knurled section 55 is reduced to form a section 51 having approximately the same diameter as that of counterbore 54. Section 51 is preferably long enough to serve as a bearing on which the upper end of sleeve 52 turns. Below bearing surface 51 the diameter of the nut is again reduced to a diameter 58 to insure clearance. Reduced portion 58 is provided with an axial threaded hole proportioned to engage the threaded end 46 of central shaft 45 and extending a substantial distance into cap nut 55.

Cap nut 55 is also provided with a locking arrangement to prevent the nut 55 from turning as sleeve 52 rotates about the central shaft 45. To accomplish this the reduced portion 58 of the locking nut is slotted diametrically for a sufiicient length 59 and the resulting semi-cylindrical portions are bent slightly toward each other. In this manner, split cylindrical portions continuously exert pressure against the threads of the central shaft and effectively prevent the nut from turning on the shaft 45 even though the shaft and lock nut rotate against sleeve 52.

Fig. 2 shows a side view of the pen assembly I l with the hinge bent in position to convert the straight blades of railroad pen ll into a double curve pen. The dotted lines show the position the blades will assume when the pen is used as a straight railroad pen.

Fig. 3 shows a modification of the invention used in Fig. 1. In this example the bridge portion l4 supporting the pens l2 and I3 is provided with fork extensions 60 and BI which serve as the lower portion of a hinge 62. Extension 60 is provided with a countersunk clearance hole 63 6 and extension 6| is provided with a threaded hole 64. The tongue portion 66 of upper hinge member 62 is also provided with a corresponding clearance hole to engage hinge axle B5.

The bottom of tongue 66 of upper hinge member 62 is beveled starting at the forward end 61 and is flush with the bottom of the fork at the other side 68. This allows the hinge to swing to one side only for a limited distance and the hinge members will align themselves in a straight line corresponding to the axis passing through the shaft 45 when the rear end of the bevel is in contact with the lower hinge slot. This hinge arrangement may also: be reversed if desired.

Fig. 4 shows the modification of Fig. 3 with the hinge bent to convert the straight-bladed pen assembly of Fig. 3 into a double cu-rve pen. Again the dotted line shows the normal position of the pen when it is to be used as a straight railroad pen.

Figs. 5 and 6 show'the manner in which the swivel handle and hinge assembly of Fig. 2 may be utilized to convert a standard single-bladed ruling pen into a curve pen.

The manner in which the device operates is as follows: When the pen is to be used as an ordinary ruling pen the two hinge members are aligned so that both axes be on the same line, the locking nut secures the handle so it will not rotate and the pen is used in a position such that any pressure is applied against the point it will force the hinge to remain straight. When the operator desires to use the pen as a curve pen he merely pushes the lower member of the hinge to its offset position placing the points of the pen or pens eccentric with respect to the longitudinal axis of the instrument and releases the handle by loosening the nut so the shaft can turn freely in the sleeve. The pen will now follow any curve either graduad or abrupt if the handle is held in a vertical position or nearly vertical position.

The advantages of the above-described hinged device are that it is possible to easily convert a straight-bladed ruling pen into a curve pen without the necessity of offsetting the blades by curving them as is normally required.

Another advantage is that since it is much simpler to manufacture a straight pen than it is to make a pen such as a curve pen having an elongated S contour the careful work required in curving the pens is eliminated effecting a considerable saving of time and material in the process of manufacture.

A further advantage is that the device ac cording to this invention permits the draftman to use a straight-bladed pen both as a curve pen and a straight ruling pen eliminating the cost of the more expensive curve pen entirely.

I claim:

1. An adapter for converting a straight-bladed ruling pen into a curve pen comprising a hinge having an upper and a lower member, said hinge members pivotally mounted with respect to each other to assume angles with respect to each other, an axial threaded bore starting at the end of said lower hinge member and extending a substantial distance therein, said threaded bore proportioned to receive the threaded end portion of the blade of a ruling pen, a shaft extending axially from the end of said upper hinge member and integrally attached thereto the upper end of said shaft provided with threads,

a cap nut on the end of said shaft and provided with threads extending a substantial distance therein to engage with the threaded portion of said shaft, a sleeve member provided with an axial bore proportioned to permit said shaft to turn freely in said sleeve member, said sleeve member sufiicientiy long to extend between the end of said upper hinge member and said cap nut.

2. An adapter according to claim 1 in which the upper and lower hinge members are provided with tongue and fork portions having cooperating stop means limiting the movement of one member only to one side of the longitudinal axis of the adapter handle when pressure is applied to the member in that direction and to align the axes of the upper and lower members with the longitudinal axis of the adapter when opposing pressure is exerted.

3. An adapter according to claim 1 in which said sleeve member is counterbored for a substantial distance starting at the upper end and said cap nut is provided with a knurled section, a bearing section adjoining said knurled section corresponding in diameter to the diameter of the counterbore in said sleeve, a cylindrical section adjoining said bearing section smaller in diameter than said bearing section and provided with. a diametrical slot extending throughout the length of said cylindrical section adjoining said bearing section.

4. A ruling pen comprising a straightbladed pen the bridge portion of which is "raped to form the fork member of a hinge, an upper hinge member having a tongue corresponding to said fork, said fork and tongue pivotally connected to each other and designed to permit the pen to pivot only to one side of the longitudinal axis passing through the instrument handle, a shaft securely attached to the end of said tongue member and extending axially therefrom, the upper end of said shaft provided with threads, 2. locking cap nut provided with a threaded bore extending a substantial distance therein to engage the threads of said shaft, a sleeve member provided with an axial bore proportioned to permit said shaft to turn freely in said sleeve, said sleeve extending between said tongue member of the hinge and said locking cap nut.

5, An adapter for converting a straight-bladed ruling pen into a curve pen comprising a hinge having upper and lower members, said members pivotally mounted with respect to each other, en-

gaging means in the end of said lower hinge member to receive an engaging member of said straight-bladed ruling pen, a shaft extending axially from the end of said upper hinge member and integrally attached thereto, the upper end of said shaft provided with threads, a cap nut on the end of said shaft and provided with threads extendin a substantial distance therein to engage with the threaded portion of said shaft, a sleeve member provided with an axial bore proportioned to permit said shaft to turn freely in said sleeve member and said sleeve member long enough to extend between the end of said upper hinge member and said cap nut.

6. An adapter for converting a straight bladed ruling pen into a curve pen comprising a hinge having an upper and a lower member, said hinge members pivotally mounted with respect to each other to permit the lower hinge member to form an angle with the longitudinal axis of the upper hinge member, said lower hinge member provided with means for securely holding a straight bladed ruling pen, a shaft extending axially from the end of said upper hinge member and integrally attached thereto, the upper end of said shaft provided with threads, a cap nut on the end of said shaft and provided with threads extending a substantial distance therein and engaging with the threaded portion of said shaft, a sleeve member provided with an axial bore proportioned to permit said shaft to turn freely in said sleeve member, said sleeve member sufiiciently long to extend between the end of said upper hinge memher and the cap nut.

GEORGE LORY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 278,697 Fischer June 5, 1883 612,889 Wirsching Oct. 25, 1898 1,181,921 Paddock May 2, 1916 1,886,253 Haff Nov. 1, 1932 2,394,452 Howard Feb. 5, 1946 FOREIGN PATENTS Number Country Date 8,934 Germany Feb. 19, 1880 317,27! Germany Dec. 13, 1919 OTHER REFERENCES K & E Catalog 37th edition, page 79, published by Keuifel & Esser 00., Hoboken, N. J 1927 

